A search for heavy neutral Higgs bosons and $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to $\tau^+\tau^-$ with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for $Z^{\prime}$ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude $\tan\beta > 1.0$ for $m_A$ = 0.25 TeV and $\tan\beta > 42$ for $m_A$ = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, $Z^{\prime}_\mathrm{SSM}$ with $m_{Z^{\prime}} < 2.42$ TeV is excluded at 95% confidence level, while $Z^{\prime}_\mathrm{NU}$ with $m_{Z^{\prime}} < 2.25$ TeV is excluded for the non-universal $G(221)$ model that exhibits enhanced couplings to third-generation fermions.

Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution in the b-tag category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be at least one b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution in the b-veto category of the 2tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution in the b-tag category of the 2tau_h channel. Despite listing this as an exclusive final state (as there must be at least one b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution for the b-inclusive selection in the 1l1tau_h channel. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The prediction for a SSM Zprime with masses of 1500, 2000 and 2500 GeV are also provided.

Observed and predicted mTtot distribution for the b-inclusive selection in the 2tau_h channel. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. The last bin includes overflows. The prediction for a SSM Zprime with masses of 1500, 2000 and 2500 GeV are also provided.

Observed and expected 95% CL upper limits on the Higgs boson production cross section times ditau branching fraction as a function of the boson mass and the relative strength of the b-associated production.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

Two dimensional likelihood scan of the gluon-gluon fusion cross section times braching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the Higgs boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. Vaules are provided for the fit to the observed data and to the expected data, which is the sum of Standard Model contributions not including the SM Higgs boson. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively.

This paper reports searches for heavy resonances decaying into $ZZ$ or $ZW$ using data from proton--proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The data, corresponding to an integrated luminosity of 36.1 fb$^{-1}$, were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The searches are performed in final states in which one $Z$ boson decays into either a pair of light charged leptons (electrons and muons) or a pair of neutrinos, and the associated $W$ boson or the other $Z$ boson decays hadronically. No evidence of the production of heavy resonances is observed. Upper bounds on the production cross sections of heavy resonances times their decay branching ratios to $ZZ$ or $ZW$ are derived in the mass range 300--5000 GeV within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions. Production through gluon--gluon fusion, Drell--Yan or vector-boson fusion are considered, depending on the assumed model.

Selection acceptance times efficiency for ggF H -> Z Z -> llqq as a function of the Higgs boson mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for VBF H -> Z Z -> llqq as a function of the Higgs boson mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for DY W' -> ZW -> llqq as a function of the W' mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for VBF W' -> ZW -> llqq as a function of the W' mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for G* -> ZZ -> llqq as a function of the W' mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Observed and expected 95% CL upper limits on $\sigma\times$BR($H\to ZZ$) at $\sqrt{s} = 13$ TeV for ggF production of a heavy Higgs boson as a function of its mass, combining $\ell\ell qq$ and $\nu\nu qq$ searches.

Observed and expected 95% CL upper limits on $\sigma\times$BR($H\to ZZ$) at $\sqrt{s} = 13$ TeV for VBF production of a heavy Higgs boson as a function of its mass, combining $\ell\ell qq$ and $\nu\nu qq$ searches.

Observed and expected 95% CL upper limits on $\sigma\times$BR($W'\to ZW$) at $\sqrt{s} = 13$ TeV for Drell-Yan production of a $W'$ boson in the HVT model as a function of its mass, combining $\ell\ell qq$ and $\nu\nu qq$ searches.

Observed and expected 95% CL upper limits on $\sigma\times$BR($W'\to ZW$) at $\sqrt{s} = 13$ TeV for VBF production of a $W'$ boson in the HVT model as a function of its mass, combining $\ell\ell qq$ and $\nu\nu qq$ searches.

Observed and expected 95% CL upper limits on $\sigma\times$BR($G_{\mathrm{KK}}\to ZZ$) at $\sqrt{s} = 13$ TeV for the production of a bulk RS graviton with couplings of $k/\overline{M}_{\mathrm{Pl}}=1$.

Observed and expected 95% CL upper limits on $\sigma\times$BR($G_{\mathrm{KK}}\to ZZ$) at $\sqrt{s} = 13$ TeV for the production of a bulk RS graviton with couplings of $k/\overline{M}_{\mathrm{Pl}}=0.5$.

A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks ($\tilde{b}_{1}$ and $\tilde{t}_{1}$) is searched for in final states with $b$-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the $\tilde{b}_{1}$ is the lightest squark and decays via $\tilde{b}_{1} \rightarrow b \tilde{\chi}^{0}_{1}$, where $\tilde{\chi}^{0}_{1}$ is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, $\tilde{b}_{1} \rightarrow b \tilde{\chi}^{0}_{1}$ and $\tilde{b}_{1} \rightarrow t \tilde{\chi}^{\pm}_{1}$, or $\tilde{t}_{1} \rightarrow t \tilde{\chi}^{0}_{1}$ and $\tilde{t}_{1} \rightarrow b \tilde{\chi}^{\pm}_{1}$, where $\tilde{\chi}^{\pm}_{1}$ is the lightest chargino and the mass difference $m_{\tilde{\chi}^{\pm}_{1}}- m_{\tilde{\chi}^{0}_{1}}$ is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95\% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models.

$m_{\mathrm{CT}}$ distribution in b0L-SRA. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

$\mathrm{min[m_{T}(jet_{1-4}, E_{T}^{miss})]}$ distribution in b0L-SRB. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

combined signal region with best expected exclusion limit in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino.

${\cal A}$ distribution in b0L-SRC. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

$\mathrm{m_{bb}}$ distribution in b1L-SRA300-2j. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

$\mathrm{m_{eff}}$ distribution in b1L-SRA. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

$\mathrm{m_{T}}$ distribution in b1L-SRB. All selection criteria are applied, except the selection on the variable that is displayed in the plot. The SM backgrounds are normalized to the values determined in the fit. The last bin includes overflows.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA300-2j signal region.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA300-2j signal region.

Cross section excluded at 95% CL for best b0L SR as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA450 signal region.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA450 signal region.

Cross section excluded at 95% CL for b0L-SRA350 as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA600 signal region.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA600 signal region.

Cross section excluded at 95% CL for b0L-SRA450 as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA750 signal region.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRA750 signal region.

Cross section excluded at 95% CL for b0L-SRB as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRB signal region.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L-SRB signal region.

Cross section excluded at 95% CL for best b1L SR as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Signal efficiency (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L- best expected signal region.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino, for the b1L- best expected signal region.

Cross section excluded at 95% CL for b1L-SRA300-2j as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for b1L-SRA450 as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for b1L-SRA600 as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for b1L-SRA750 as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for b1L-SRB as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for best combination as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for A-LowMass combination as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for A-HighMass combination as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

Cross section excluded at 95% CL for B combination as a function of the sbottom and neutralino masses, for a pair produced sbottom with asymmetric decay into a bottom and a neutralino or a top and a chargino.

The results of a search for squarks and gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using proton--proton collision data at a center-of-mass energy of $\sqrt{s}$ = 13 TeV are presented. The dataset used was recorded during 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 36.1 $fb^{-1}$. No significant excess beyond the expected background is found. Exclusion limits at 95% confidence level are set in a number of supersymmetric scenarios, reaching masses up to 2.1 TeV for gluino pair production and up to 1.25 TeV for squark pair production.

$m_{\mathrm{T}}$ distribution for events satisfying all the 2J b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{eff}}$ distribution in 2J b-veto signal regions after fit. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 2J b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 2J b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 2J b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{eff}}$ distribution in 6J b-veto signal regions after fit. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{eff}}$ distribution in 2J b-tag signal regions after fit. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 4J low-x b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 4J low-x b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 4J low-x b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 4J low-x b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{eff}}$ distribution in 6J b-tag signal regions after fit. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{eff}}$ distribution in 9J signal regions after fit. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 4J high-x b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 4J high-x b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 4J high-x b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 4J high-x b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 6J b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 6J b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 6J b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$E_{\mathrm T}^{\mathrm{miss}}$ distribution for events satisfying all the 6J b-tag signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

$m_{\mathrm{T}}$ distribution for events satisfying all the 9J signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.

Cutflow table for the 9J discovery signal region with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 6J discovery signal region (targetting gluino decays) with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 4J high-x discovery signal region with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 4J low-x discovery signal region (targetting gluino decays) with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 2J discovery signal region with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 4J low-x discovery signal region (targetting squark decays) with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

Cutflow table for the 6J discovery signal region (targetting squark decays) with a representative target signal model. The weighted numbers are normalized to 36.1 fb$^{-1}$ and rounded to the statistical error. The selection called "Filter" is introduced for initial data reduction. It selects events with at least one soft electron or muon ($3.5 < p_\mathrm{T} < 25$ GeV for muons and $4.5 < p_\mathrm{T} < 25$ GeV for electrons) in which an $E_\mathrm{T}^\mathrm{miss}$ trigger has fired or events with at least one hard electron or muon ($p_\mathrm{T} >$25 GeV).

A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of $pp$ collisions corresponding to an integrated luminosity of 36.1 fb$^{-1}$, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=$ 13 TeV. No significant deviation from the Standard Model background expectation is observed. Limits are derived in scenarios of $\tilde{\chi}_{1}^{+}\tilde{\chi}_{1}^{-}$ pair production and of $\tilde{\chi}_{1}^{\pm}\tilde{\chi}_{2}^{0}$ and $\tilde{\chi}_{1}^{+}\tilde{\chi}_{1}^{-}$ production. Chargino masses up to 630 GeV are excluded at 95\% confidence level in the scenario of direct production of $\tilde{\chi}_{1}^{+}\tilde{\chi}_{1}^{-}$ for a massless $\tilde{\chi}_{1}^{0}$. Common $\tilde{\chi}_{1}^{\pm}$, $\tilde{\chi}_{2}^{0}$ masses up to 760 GeV are excluded in the case of production of $\tilde{\chi}_{1}^{\pm}\tilde{\chi}_{2}^{0}$ and $\tilde{\chi}_{1}^{+}\tilde{\chi}_{1}^{-}$ assuming a massless $\tilde{\chi}_{1}^{0}$.

The $E_{\mathrm T}^{\mathrm{miss}}$ distribution in the $W$-CR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The contribution of $W$+jets events is scaled to the fit result. The multi-jet contribution is estimated from data using the OS-SS method. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events.

The $E_{\mathrm T}^{\mathrm{miss}}$ distribution in the multi-jet background VR-F for SR-lowMass. The stacked histograms show the contribution of the non-multi-jet SM backgrounds from MC simulation. The multi-jet contribution is estimated from data using the ABCD method. The hatched bands represent the combined statistical and systematic uncertainties in the sum of the SM backgrounds shown. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The last bin in the left panels includes the overflow events.

The $m_{\mathrm{T2}}$ distribution before the $m_{\mathrm{T2}}$ requirement is applied for SR-lowMass region, where the arrow indicates the position of the cut in the signal region. The stacked histograms show the expected SM backgrounds. The multi-jet contribution is estimated from data using the ABCD method. The contributions of multi-jet and $W$+jets events are scaled with the corresponding normalisation factors. The hatched bands represent the sum in quadrature of systematic and statistical uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the total SM background estimate. The last bin includes the overflow events.

Cut flow for the reference point 1 (CHARGINO1 NEUTRALINO2 production) in SR-lowMass. The column labelled $N_{raw}$ shows the results for the generated number of events, while $N_{weighted}$ includes all correction factors applied to simulation, and is normalised to 36.1 fb$^{-1}$. The quoted uncertainties are statistical only. At the step ``at least two medium tau candidates, matched to trigger objects' the following requirements are applied: the event is recorded using either the asymmetric di-tau trigger or the di-tau+$E_{\mathrm T}^{\mathrm{miss}}$ trigger, and the two matched tau candidates must be of medium quality. If the event has been selected by the asymmetric di-tau trigger, the two tau candidates are required to have ${p}_{\mathrm{T}, \tau_1}>$ 95 GeV and ${p}_{\mathrm{T}, \tau_2}>$ 65 GeV. If the event has been selected by the di-tau+$E_{\mathrm T}^{\mathrm{miss}}$ trigger, the two tau candidates are required to have ${p}_{\mathrm{T}, \tau_1}>$ 50 GeV, ${p}_{\mathrm{T}, \tau_2}>$ 40 GeV, and $E_{\mathrm T}^{\mathrm{miss}}$ > 150 GeV is required.}

The $m_{\mathrm{T2}}$ distribution in the multi-jet background VR-F for SR-lowMass. The stacked histograms show the contribution of the non-multi-jet SM backgrounds from MC simulation. The multi-jet contribution is estimated from data using the ABCD method. The hatched bands represent the combined statistical and systematic uncertainties in the sum of the SM backgrounds shown. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The last bin in the left panels includes the overflow events.

The $m_{\mathrm{T2}}$ distribution in the $W$-CR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The contribution of $W$+jets events is scaled to the fit result. The multi-jet contribution is estimated from data using the OS-SS method. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events.

The $m_{\mathrm{T2}}$ distribution before the $m_{\mathrm{T2}}$ requirement is applied for SR-highMass region, where the arrow indicates the position of the cut in the signal region. The stacked histograms show the expected SM backgrounds. The multi-jet contribution is estimated from data using the ABCD method. The contributions of multi-jet and $W$+jets events are scaled with the corresponding normalisation factors. The hatched bands represent the sum in quadrature of systematic and statistical uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the total SM background estimate. The last bin includes the overflow events.

Cut flow for the reference point 2 (CHARGINO1 CHARGINO1 production) in SR-highMass. The column labelled $N_{raw}$ shows the results for the generated number of events, while $N_{weighted}$ includes all correction factors applied to simulation, and is normalised to 36.1 fb$^{-1}$. The quoted uncertainties are statistical only. At the step ``at least two medium tau candidates, matched to trigger objects' the following requirements are applied: the event is recorded using either the asymmetric di-tau trigger or the di-tau+$E_{\mathrm T}^{\mathrm{miss}}$ trigger, and the two matched tau candidates must be of medium quality. If the event has been selected by the asymmetric di-tau trigger, the two tau candidates are required to have ${p}_{\mathrm{T}, \tau_1}>$ 95 GeV and ${p}_{\mathrm{T}, \tau_2}>$ 65 GeV. If the event has been selected by the di-tau+$E_{\mathrm T}^{\mathrm{miss}}$ trigger, the two tau candidates are required to have ${p}_{\mathrm{T}, \tau_1}>$ 50 GeV, ${p}_{\mathrm{T}, \tau_2}>$ 40 GeV, and $E_{\mathrm T}^{\mathrm{miss}}$ > 150 GeV is required.}

The $E_{\mathrm T}^{\mathrm{miss}}$ distribution in the multi-jet background VR-F for SR-highMass. The stacked histograms show the contribution of the non-multi-jet SM backgrounds from MC simulation. The multi-jet contribution is estimated from data using the ABCD method. The hatched bands represent the combined statistical and systematic uncertainties in the sum of the SM backgrounds shown. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The last bin in the left panels includes the overflow events.

The $m_{\mathrm{T2}}$ distribution in the multi-jet background VR-F for SR-highMass. The stacked histograms show the contribution of the non-multi-jet SM backgrounds from MC simulation. The multi-jet contribution is estimated from data using the ABCD method. The hatched bands represent the combined statistical and systematic uncertainties in the sum of the SM backgrounds shown. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The last bin in the left panels includes the overflow events.

The $E_{\mathrm T}^{\mathrm{miss}}$ distribution in the $W$-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The contribution of $W$+jets events is scaled to the fit result. The multi-jet contribution is estimated from data using the $OS--SS$ method. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events.

The $m_{\mathrm{T2}}$ distribution in the $W$-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The contribution of $W$+jets events is scaled to the fit result. The multi-jet contribution is estimated from data using the $OS--SS$ method. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events.

The $m_{\mathrm{T2}}$ distribution in the $Z$-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The multi-jet contribution is estimated from data using the ABCD method, using CRs obtained with the same technique used for the SRs. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events except for the upper left panel.

The $m_{\mathrm{T2}}$ distribution in the Top-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The multi-jet contribution is estimated from data using the ABCD method, using CRs obtained with the same technique used for the SRs. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events except for the upper left panel.

The $m_{\mathrm{T2}}$ distribution in the $WW$-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The multi-jet contribution is negligible and not considered. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events except for the upper left panel.

The $m_{\mathrm{T2}}$ distribution in the $ZZ$-VR region. The SM backgrounds other than multi-jet production are estimated from MC simulation. The multi-jet contribution is negligible and not considered. The hatched bands represent the combined statistical and systematic uncertainties of the total SM background. For illustration, the distributions of the SUSY reference points are also shown as dashed lines. The lower panels show the ratio of data to the SM background estimate. The last bin includes the overflow events except for the upper left panel.

The results of a search for direct pair production of top squarks in events with two opposite-charge leptons (electrons or muons) are reported, using 36.1 fb$^{-1}$ of integrated luminosity from proton--proton collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector at the Large Hadron Collider. To cover a range of mass differences between the top squark $\tilde{t}$ and lighter supersymmetric particles, four possible decay modes of the top squark are targeted with dedicated selections: the decay $\tilde{t} \rightarrow b \tilde{\chi}_{1}^{\pm}$ into a $b$-quark and the lightest chargino with $\tilde{\chi}_{1}^{\pm} \rightarrow W \tilde{\chi}_{1}^{0}$, the decay $\tilde{t} \rightarrow t \tilde{\chi}_{1}^{0}$ into an on-shell top quark and the lightest neutralino, the three-body decay $\tilde{t} \rightarrow b W \tilde{\chi}_{1}^{0}$ and the four-body decay $\tilde{t} \rightarrow b \ell \nu \tilde{\chi}_{1}^{0}$. No significant excess of events is observed above the Standard Model background for any selection, and limits on top squarks are set as a function of the $\tilde{t}$ and $\tilde{\chi}_{1}^{0}$ masses. The results exclude at 95% confidence level $\tilde{\chi}_{1}^{0}$ masses up to about 720 GeV, extending the exclusion region of supersymmetric parameter space covered by previous searches.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Two-body selection distribution of $n_{jets}$ in CR$^{2-body}_{top}$ after the background fits. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Four-body selection distributions of $R_{2\ell 4j}$ for events with at least 2 jets (with the two leading required not be identified as $b$-jets), a leading jet $p_{T} >150$ GeV and satisfying the SR$^{4-body}$ requirements on the leptons. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The fake and non-prompt lepton backgrounds are estimated from data, the other backgrounds are estimated from MC simulation with a background fit as described in Section6. The rightmost bin of each plot includes overflow events. In order to enhance the contribution from fake or non-prompt leptons, the lepton pair is required to have the same charge.

Two-body selection distribution of $E_{T}^{miss}$ for events satisfying all the VR$^{2-body}_{VV-DF}$ selections, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Two-body selection background fit results for the CRs of the SRA$^{2-body}_{180}$ and SRB$^{2-body}_{140}$ background fits. The nominal expectations from MC simulation are given for comparison for those backgrounds (top, $VV$-SF, ttZ and $VZ$) that are normalised to data in dedicated CRs. The `Others category contains the contributions from $ttW$, $tth$, $ttWW$, $ttt$, $tttt$, $Wh$, $ggh$ and $Zh$ production. Combined statistical and systematic uncertainties are given. Entries marked ``--'' indicate a negligible background contribution. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty extends to zero predicted events, in which case the negative uncertainty is truncated.

Two-body selection distribution of $R_{2\ell 2j}$ in $CR^{2-body}_{VV-SF}$ after the background fits. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Four-body selection distributions of $R_{2\ell}$ for events with at least 2 jets (with the two leading required not be identified as $b$-jets), a leading jet $p_{T} >150$ GeV and satisfying the SR$^{4-body}$ requirements on the leptons. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The fake and non-prompt lepton backgrounds are estimated from data, the other backgrounds are estimated from MC simulation with a background fit as described in Section6. The rightmost bin of each plot includes overflow events. In order to enhance the contribution from fake or non-prompt leptons, the lepton pair is required to have the same charge.

Two-body selection distribution of $m_{T2}^{ll}$ for events satisfying all the VR$^{2-body}_{t\bar{t}}$ selections, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Three-body selection background fit results for the CRs of the SR$^{3-body}_{W}$ and SR$^{3-body}_{t}$ background fit. The nominal expectations from MC simulation are given for comparison for those backgrounds (ttbar, $VV$-DF and $VV$-SF) that are normalised to data in dedicated CRs.Combined statistical and systematic uncertainties are given. Entries marked ``--'' indicate a negligible background contribution. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty extends to zero predicted events, in which case the negative uncertainty is truncated.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Two-body selection distribution of $E_{T,corr}^{miss}$ in $CR_{ttZ}$ after the background fits. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Expected exclusion contour as a function of $m_{\tilde{t}_1}$ and $m_{\tilde{\chi}^0_1}$ in the pMSSM model described in the text. Pair production of $\tilde{t}_1$ and $\tilde{b}_1$ are considered. Limits are set for both the positive (red in the figure) and negative (blue in the figure) values of $\mu$. The dashed and dotted grey lines indicate constant values of the $\tilde{b}_1$ mass. The signal models included within the shown contours are excluded at 95% CL. The dashed lines and the shaded band are the expected limit and its $\pm1\sigma$ uncertainty. The thick solid line is the observed limit for the central value of the signal cross-section. The expected and observed limits do not include the effect of the theoretical uncertainties in the signal cross-section.

Observed exclusion contour as a function of $m_{\tilde{t}_1}$ and $m_{\tilde{\chi}^0_1}$ in the pMSSM model described in the text. Pair production of $\tilde{t}_1$ and $\tilde{b}_1$ are considered. Limits are set for both the positive (red in the figure) and negative (blue in the figure) values of $\mu$. The dashed and dotted grey lines indicate constant values of the $\tilde{b}_1$ mass. The signal models included within the shown contours are excluded at 95% CL. The dashed lines and the shaded band are the expected limit and its $\pm1\sigma$ uncertainty. The thick solid line is the observed limit for the central value of the signal cross-section. The expected and observed limits do not include the effect of the theoretical uncertainties in the signal cross-section.

Upper limits on cross-sections (in fb) at 95% CL for each signal model, assuming the pMSSM model described in the text. Pair production of $\tilde{t}_{1}$ and $\tilde{b}_{1}$ are considered. Limits are set for both positive (top) and negative (bottom) values of $\mu$.

Two-body selection distribution of $m_{T2}^{ll}$ for events satisfying all the VR$^{2-body}_{t\bar{t},3j}$ selections, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Expected exclusion contour as a function of $m_{\tilde{t}_1}$ and $m_{\tilde{\chi}^0_1}$ in the pMSSM model described in the text. Pair production of $\tilde{t}_1$ and $\tilde{b}_1$ are considered. Limits are set for both the positive (red in the figure) and negative (blue in the figure) values of $\mu$. The dashed and dotted grey lines indicate constant values of the $\tilde{b}_1$ mass. The signal models included within the shown contours are excluded at 95% CL. The dashed lines and the shaded band are the expected limit and its $\pm1\sigma$ uncertainty. The thick solid line is the observed limit for the central value of the signal cross-section. The expected and observed limits do not include the effect of the theoretical uncertainties in the signal cross-section.

Four-body selection background fit results for the CRs of the SR$^{4-body}$ background fit. The nominal expectations from MC simulation are given for comparison for those backgrounds ($t\bar t$, $VV$ and $Z_{\tau\tau}$) that are normalised to data in dedicated CRs. Combined statistical and systematic uncertainties are given. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty extends to zero predicted events, in which case the negative uncertainty is truncated.

Two-body selection distribution of $E_{T,corr}^{miss}$ in $CR_{VZ}$ after the background fits. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Observed exclusion contour as a function of $m_{\tilde{t}_1}$ and $m_{\tilde{\chi}^0_1}$ in the pMSSM model described in the text. Pair production of $\tilde{t}_1$ and $\tilde{b}_1$ are considered. Limits are set for both the positive (red in the figure) and negative (blue in the figure) values of $\mu$. The dashed and dotted grey lines indicate constant values of the $\tilde{b}_1$ mass. The signal models included within the shown contours are excluded at 95% CL. The dashed lines and the shaded band are the expected limit and its $\pm1\sigma$ uncertainty. The thick solid line is the observed limit for the central value of the signal cross-section. The expected and observed limits do not include the effect of the theoretical uncertainties in the signal cross-section.

Upper limits on cross-sections (in fb) at 95% CL for each signal model, assuming the pMSSM model described in the text. Pair production of $\tilde{t}_{1}$ and $\tilde{b}_{1}$ are considered. Limits are set for both positive (top) and negative (bottom) values of $\mu$.

Three-body selection distributions of $M_{\Delta}^{R}$ in events that satisfy all the $VR^{3-body}_{t\bar{t}}$ selection criteria after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $R_{p_{T}}$ in $CR^{3-body}_{t\bar{t}}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Three-body selection distributions of $R_{p_{T}}$ in events that satisfy all the $VR^{3-body}_{VV-SF}$ selection criteria after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $cos\theta_{b}$ in $CR^{3-body}_{VV-DF}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Two-body selection distributions of $m_{T2}^{ll}$ for events satisfying the selection criteria of the six SRs, except for the one on $m_{T2}^{ll}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Three-body selection distributions of $R_{p_{T}}$ in events that satisfy all the $VR^{3-body}_{VV-DF}$ selection criteria after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $M_{\Delta}^{R}$ in $CR^{3-body}_{VV-SF}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $R_{p_{T}}$ in same-flavour events that satisfy all the SR$^{3-body}_{W}$ selection criteria except for the one on $R_{p_{T}}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Two-body selection background fit results for SR(A,B)$^{2-body}_{x,y}$ regions, where x and y denote the low and high edges of the bin. Combined statistical and systematic uncertainties are given. Uncertainties on the predicted background event yields are quoted as symmetric.

Four-body selection distributions of $E^{miss}_{T}$ for events satisfying all the VR$^{4-body}_{t\bar{t}}$ selections, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The fake and non-prompt lepton backgrounds are estimated from data, the other backgrounds are estimated from MC simulation with a background fit as described in Section 6}. The rightmost bin of each plot includes overflow events.

Four-body selection distributions of the $p_{T}(j_1)$ in CR$^{4-body}_{t\bar{t}}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $R_{p_{T}}$ in different-flavour events that satisfy all the SR$^{3-body}_{W}$ selection criteria except for the one on $R_{p_{T}}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Four-body selection distributions of the $R_{2\ell}$ in CR$^{4-body}_{VV}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $M_{\Delta}^{R}$ in same-flavour events that satisfy all the SR$^{3-body}_{t}$ selection criteria except for the one on $M_{\Delta}^{R}$, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Four-body selection distributions of the $E^{miss}_{T}$ in CR$^{4-body}_{Z\tau\tau}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and detector-related systematic uncertainty. The rightmost bin of each plot includes overflow events.

Three-body selection distributions of $M_{\Delta}^{R}$ in different-flavour events that satisfy all the SR$^{3-body}_{t}$ selection criteria except for the one on $M_{\Delta}^{R}$ after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Two-body selection background fit results for the VR in the SRA$^{2-body}$ and SRB$^{2-body}_{140}$ background-only fit. The nominal expectations from MC simulation are given for comparison for those backgrounds ($t\bar t$, $t\bar t Z$) that are normalised to data in dedicated CRs. The Others category contains the contributions from $t\bar t W$, $t\bar t h$, $t\bar t WW$, $t\bar t t$, $t\bar t t\bar t$, $Wh$, $ggh$ and $Zh$ production. Combined statistical and systematic uncertainties are given. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty reaches down to zero predicted events, in which case the negative uncertainty is truncated.

Four-body selection distributions of $R_{2\ell 4j}$ for events satisfying all the SR$^{4-body}$ selections but for the one on the variable shown in the figure, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Four-body selection distributions of $R_{2\ell}$ for events satisfying all the SR$^{4-body}$ selections but for the one on the variable shown in the figure, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows indicate the signal region selection criteria.

Three-body selection background fit results for the VRs in the SR$^{3-body}_{W}$ and SR$^{3-body}_{t}$ background-only fits. The nominal expectations from MC simulation are given for comparison for those backgrounds ($t\bar t$, $VV$ and $Z_{\tau\tau}$) that are normalised to data in dedicated CRs. The Others category contains the contributions from $t\bar t W$, $t\bar t h$, $t\bar t WW$, $t\bar t $, $t\bar t t\bar t$ , $Wh$, $ggh$ and $Zh$ production. Combined statistical and systematic uncertainties are given. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty reaches down to zero predicted events, in which case the negative uncertainty is truncated.

Four-body selection background fit results for the VRs in the SR$^{4-body}$ background-only fit. The nominal expectations from MC simulation are given for comparison for those backgrounds ($t\bar t$, $VV$ and $Z_{\tau\tau}$) that are normalised to data in dedicated CRs. The Others category contains the contributions from $t\bar t W$, $t\bar t h$, $t\bar t WW$, $t\bar t $, $t\bar t t\bar t$ , $Wh$, $ggh$ and $Zh$ production. Combined statistical and systematic uncertainties are given. Uncertainties on the predicted background event yields are quoted as symmetric except where the negative uncertainty reaches down to zero predicted events, in which case the negative uncertainty is truncated.

Model-independent 95% CL upper limits on the visible cross-section ($\sigma_{vis}$) of new physics, the visible number of signal events ($S^{95}_{\rm obs}$), the visible number of signal events ($S^{95}_{\rm exp}$) given the expected number of background events (and $\pm1\sigma$ excursions on the expectation), and the discovery $p$-value ($p(s = 0)$), all calculated with pseudo-experiments, are shown for each SR.

A search is presented for particles that decay producing a large jet multiplicity and invisible particles. The event selection applies a veto on the presence of isolated electrons or muons and additional requirements on the number of b-tagged jets and the scalar sum of masses of large-radius jets. Having explored the full ATLAS 2015-2016 dataset of LHC proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$, which corresponds to 36.1 fb$^{-1}$ of integrated luminosity, no evidence is found for physics beyond the Standard Model. The results are interpreted in the context of simplified models inspired by R-parity-conserving and R-parity-violating supersymmetry, where gluinos are pair-produced. More generic models within the phenomenological minimal supersymmetric Standard Model are also considered.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-7j80-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with no b-jet requirement and a minimum transverse momentum of 50 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-7j80-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with one inclusive b-jet required and a minimum transverse momentum of 50 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-7j80-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with two inclusive b-jets required and a minimum transverse momentum of 50 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j80-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with no b-jet requirement and a minimum transverse momentum of 80 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j80-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with one inclusive b-jet required and a minimum transverse momentum of 80 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j80-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the flavour stream with two inclusive b-jets required and a minimum transverse momentum of 80 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j80-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the fat-jet stream with MJSigma above 340 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j80-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Degree of multijet closure for signal and vaidation regions (prior to the leptonic background fit) for the fat-jet stream with MJSigma above 500 GeV. The solid lines are the pre-fit predicted numbers of events and the points are the observed numbers. The blue hatched band shows only the statistical (MC and data) uncertainty on the background estimate. The template closure uncertainty for each SR bin is given by the maximal deviation of data from prediction in any non-SR bin to its left on this plot (although those for 80 GeV regions are independent of deviations in 50 GeV regions).

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j80-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j50-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-8j50-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j50-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-9j50-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-10j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-10j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-10j50-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-10j50-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-11j50-0b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-11j50-1b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

Number of signal events expected for 36.1 fb$^{-1}$ at different stages of the event selection for the signal region SR-11j50-2b in a pMSSM inspired model where m($\tilde{g}$) = 1400 GeV and m($\tilde{\chi}_{0}^{1}$) = 200 GeV.

A search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $q\bar{q}^{(\prime)}b\bar{b}$ final state is described. The search uses 36.1 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} =$ 13 TeV collected by the ATLAS detector at the CERN Large Hadron Collider in 2015 and 2016. The data are in agreement with the Standard Model expectations, with the largest excess found at a resonance mass of 3.0 TeV with a local (global) significance of 3.3 (2.1) $\sigma$. The results are presented in terms of constraints on a simplified model with a heavy vector triplet. Upper limits are set on the production cross-section times branching ratio for resonances decaying to a $W$ ($Z$) boson and a Higgs boson, itself decaying to $b\bar{b}$, in the mass range between 1.1 and 3.8 TeV; the limits range between 83 and 1.6 fb (77 and 1.1 fb) at 95% confidence level.

Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a $Z/\gamma^\ast$ boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb$^{-1}$ of proton--proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13 TeV and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper.

A search is presented for the pair production of heavy vector-like $T$ and $B$ quarks, primarily targeting the $T$ quark decays to a $W$ boson and a $b$-quark. The search is based on $36.1$ fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton-plus-jets final state, including at least one $b$-tagged jet and a large-radius jet identified as originating from the hadronic decay of a high-momentum $W$ boson. No significant deviation from the Standard Model expectation is observed in the reconstructed $T$ mass distribution. The observed 95\% confidence level lower limit on the $T$ mass are 1350 GeV assuming 100\% branching ratio to $Wb$. In the SU(2) singlet scenario, the lower mass limit is 1170 GeV. This search is also sensitive to a heavy vector-like $B$ quark decaying to $Wt$ and other final states. The results are thus reinterpreted to provide a 95\% confidence level lower limit on the $B$ quark mass at 1250 GeV assuming 100\% branching ratio to $Wt$; in the SU(2) singlet scenario, the limit is 1080 GeV. Mass limits on both $T$ and $B$ production are also set as a function of the decay branching ratios. The 100\% branching ratio limits are found to be applicable to heavy vector-like $Y$ and $X$ production that decay to $Wb$ and $Wt$, respectively.

Measurements of transverse energy-energy correlations and their associated asymmetries in multi-jet events using the ATLAS detector at the LHC are presented. The data used correspond to $\sqrt{s} = 8$ TeV proton-proton collisions with an integrated luminosity of 20.2 fb$^{-1}$. The results are presented in bins of the scalar sum of the transverse momenta of the two leading jets, unfolded to the particle level and compared to the predictions from Monte Carlo simulations. A comparison with next-to-leading-order perturbative QCD is also performed, showing excellent agreement within the uncertainties. From this comparison, the value of the strong coupling constant is extracted for different energy regimes, thus testing the running of $\alpha_s(\mu)$ predicted in QCD up to scales over 1 TeV. A global fit to the transverse energy-energy correlation distributions yields $\alpha_s(m_Z) = 0.1162 \pm 0.0011 \mbox{ (exp.)}^{+0.0084}_{-0.0070} \mbox{ (theo.)}$, while a global fit to the asymmetry distributions yields a value of $\alpha_s(m_Z) = 0.1196 \pm 0.0013 \mbox{ (exp.)}^{+0.0075}_{-0.0045} \mbox{ (theo.)}$.

Several extensions of the Standard Model predict associated production of dark-matter particles with a Higgs boson. Such processes are searched for in final states with missing transverse momentum and a Higgs boson decaying to a $b\bar b$ pair with the ATLAS detector using 36.1 fb$^{-1}$ of $pp$ collisions at a center-of-mass energy of 13 TeV at the LHC. The observed data are in agreement with the Standard Model predictions and limits are placed on the associated production of dark-matter particles and a Higgs boson.

The results of a search for new heavy $W^\prime$ bosons decaying to an electron or muon and a neutrino using proton-proton collision data at a centre-of-mass energy of $\sqrt{s} = 13$ TeV are presented. The dataset was collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 36.1 fb$^{-1}$. As no excess of events above the Standard Model prediction is observed, the results are used to set upper limits on the $W^\prime$ boson cross-section times branching ratio to an electron or muon and a neutrino as a function of the $W^\prime$ mass. Assuming a $W^\prime$ boson with the same couplings as the Standard Model $W$ boson, $W^\prime$ masses below 5.1 TeV are excluded at the 95% confidence level.

A search for direct top squark pair production resulting in events with either a same-flavour opposite-sign dilepton pair with invariant mass compatible with a $Z$ boson or a pair of jets compatible with a Standard Model (SM) Higgs boson ($h$) is presented. Requirements on additional leptons, jets, jets identified as originating from $b$-quarks, and missing transverse momentum are imposed to target the other decay products of the top squark pair. The analysis is performed using proton-proton collision data at $\sqrt{s}=13$ TeV collected with the ATLAS detector at the LHC in 2015--2016, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. No excess is observed in the data with respect to the SM predictions. The results are interpreted in two sets of models. In the first set, direct production of pairs of lighter top squarks ($\tilde{t}_1$) with long decay chains involving $Z$ or Higgs bosons is considered. The second set includes direct pair production of the heavier top squark pairs ($\tilde{t}_2$) decaying via $\tilde{t}_2 \rightarrow Z \tilde{t}_1 $ or $\tilde{t}_2 \rightarrow h \tilde{t}_1$. The results exclude at 95\% confidence level $\tilde{t}_2$ and $\tilde{t}_1$ masses up to about 800 GeV, extending the exclusion region of supersymmetric parameter space covered by previous LHC searches.

Distribution of $m_{bb}$ for events passing all the signal selection requirements, except that on $m_{bb}$, for SR$^{1\ell 4b}_A$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Background fit results for the control and validation regions in the 1$\ell$4$b$ selection. The nominal predictions from MC simulation are given for comparison for the $t\bar{t}$ background, which is normalised to data. The "Others" category contains the contributions from $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $tZ$, and $tWZ$ production. Combined statistical and systematic uncertainties are given. The individual uncertainties can be correlated and do not necessarily add in quadrature to the total systematic uncertainty.

Summary of the main systematic uncertainties and their impact (in %) on the total SM background prediction in each of the signal regions studied. The total systematic uncertainty can be different from the sum in quadrature of individual sources due to the correlations between them resulting from the fit to the data. The quoted theoretical uncertainties include modelling and cross-section uncertainties.

Observed and expected numbers of events the three 3$\ell$1$b$ Signal regions. The nominal predictions from MC simulation are given for comparison for those backgrounds, $t\bar{t} Z$, multi-boson that are normalised to data in dedicated control regions. For SR$^{3\ell 1b}_A$, SR$^{3\ell 1b}_B$ and SR$^{3\ell 1b}_C$, the "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production. Combined statistical and systematic uncertainties are given. Signal model-independent 95% CL upper limits on the visible BSM cross-section ($\sigma_{\mathrm{vis}}$), the visible number of signal events ($S^{95}_{\rm obs}$), the number of signal events ($S^{95}_{\rm exp}$) given the expected number of background events (and $\pm1\sigma$ variations of the expected background), and the discovery $p$-value ($p(s = 0)$), all calculated with pseudo-experiments, are also shown for each signal region.

Observed and expected numbers of events in the three 1$\ell$4$b$ signal regions. The nominal predictions from MC simulation are given for comparison for those backgrounds, $t\bar{t}$, are normalised to data in dedicated control regions. For SR$^{1\ell 4b}_A$, SR$^{1\ell 4b}_B$ and SR$^{1\ell 4b}_C$, the "Others" category contains the contributions from $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $tZ$, and $tWZ$ production. Combined statistical and systematic uncertainties are given. Signal model-independent 95% CL upper limits on the visible BSM cross-section ($\sigma_{\mathrm{vis}}$), the visible number of signal events ($S^{95}_{\rm obs}$), the number of signal events ($S^{95}_{\rm exp}$) given the expected number of background events (and $\pm1\sigma$ variations of the expected background), and the discovery $p$-value ($p(s = 0)$), all calculated with pseudo-experiments, are also shown for each signal region.

Illustration of the best expected signal region per signal grid point for the $\tilde{t}_2 \rightarrow h\tilde{t}_1$ models with $\tilde{t}_1\to t\tilde{\chi}^0_1$. This mapping is used for the final combined exclusion limits 1 = A, 2 = B, 3 = C.

Illustration of the best expected signal region per signal grid point for the $\tilde{t}_2 \rightarrow Z\tilde{t}_1$ models with $\tilde{t}_1\to t\tilde{\chi}^0_1$. This mapping is used for the final combined exclusion limits 1 = A, 2 = B, 3 = C.

Jet multiplicity distributions in VR$^{1\ell 4b}_C$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

Jet multiplicity distributions in VR$^{1\ell 4b}_B$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

Jet multiplicity distributions in VR$^{1\ell 4b}_A$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

E$^{T}_\text{miss}$ distributions in VR$^{1\ell 4b}_C$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

E$^{T}_\text{miss}$ distributions in VR$^{1\ell 4b}_B$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

$E^{T}_\text{miss}$ distributions in VR$^{1\ell 4b}_A$ for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

Jet multiplicity for events with at least 3 jets, one $b$-tagged jets for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. In order to enhance the contribution from fake or non-prompt leptons from $t\bar{t}$ events, the events are required to have at least one different flavour lepton pair and no same flavour pair with opposite charge.

$E^{T}_\text{miss}$ for events with at least 3 jets, one $b$-tagged jets for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. In order to enhance the contribution from fake or non-prompt leptons from $t\bar{t}$ events, the events are required to have at least one different flavour lepton pair and no same flavour pair with opposite charge.

$p_{\rm T}^{\ell\ell}$ for events with at least 3 jets, one $b$-tagged jets for an integrated luminosity of 36.1 fb$^{-1}$. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. In order to enhance the contribution from fake or non-prompt leptons from $t\bar{t}$ events, the events are required to have at least one different flavour lepton pair and no same flavour pair with opposite charge.

Jet multiplicity distributions in control regions CR$^{3\ell 1b}_{t\bar{t}Z}$, after normalising the $t\bar{t}Z$ and multi-boson background processes via the simultaneous fit described in Section 5. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty in the background prediction. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

Jet multiplicity distributions in control region CR$^{3\ell 1b}_{VV}$, after normalising the $t\bar{t}Z$ and multi-boson background processes via the simultaneous fit described in Section 5. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty in the background prediction. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production.

Jet multiplicity distributions in control regions CR$^{1\ell 4b}_{t\bar{t},A}$, after normalising the $t\bar{t}$ background process via the simultaneous fit described in Section 5. The $t\bar{t}$ background normalisation is constrained to the data observation for jet multiplicity values above the requirements shown in Table 6. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production. The last bin in each figure contains the overflow. The lower panels show the ratio of the observed data to the total SM background prediction, with the bands representing the total uncertainty in the background prediction.

Jet multiplicity distributions in control regions CR$^{1\ell 4b}_{t\bar{t},B}$, after normalising the $t\bar{t}$ background process via the simultaneous fit described in Section 5. The $t\bar{t}$ background normalisation is constrained to the data observation for jet multiplicity values above the requirements shown in Table 6. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production. The last bin in each figure contains the overflow. The lower panels show the ratio of the observed data to the total SM background prediction, with the bands representing the total uncertainty in the background prediction.

Jet multiplicity distributions in control regions CR$^{1\ell 4b}_{t\bar{t},C}$, after normalising the $t\bar{t}$ background process via the simultaneous fit described in Section 5. The $t\bar{t}$ background normalisation is constrained to the data observation for jet multiplicity values above the requirements shown in Table 6. The contributions from all SM backgrounds are shown as a histogram stack; the bands represent the total uncertainty. The "Others" category contains the contributions from $t\bar{t} h$, $t\bar{t} WW$, $t\bar{t} t$, $t\bar{t} t\bar{t}$, $Wh$, and $Zh$ production. The last bin in each figure contains the overflow. The lower panels show the ratio of the observed data to the total SM background prediction, with the bands representing the total uncertainty in the background prediction.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{3\ell 1b}_A$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{1\ell 4b}_A$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{3\ell 1b}_B$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{1\ell 4b}_B$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{3\ell 1b}_C$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Distribution of $E^{T}_\text{miss}$ for events passing all the signal candidate selection requirements, except that on $E^{T}_\text{miss}$, for SR$^{1\ell 4b}_C$ after the background fit described in Section 5. The contributions from all SM backgrounds are shown; the bands represent the total uncertainty. The last bin in each figure contains the overflow.

Expected exclusion limits at 95% CL from the analysis of $36.1 \; \text{fb}^{-1}$ of 13 TeV $pp$ collision data as a function of the masses of the $\tilde{t}_2$ and $\tilde{\chi}^0_1$, for a fixed $m(\tilde{t}_1)-m(\tilde{\chi}^0_1) = 180$ GeV and assuming a $\text{BR}(\tilde{t}_2 \to Z\tilde{t}_1) = 1$.

Observed exclusion limits at 95% CL from the analysis of $36.1 \; \text{fb}^{-1}$ of 13 TeV $pp$ collision data as a function of the masses of the $\tilde{t}_2$ and $\tilde{\chi}^0_1$, for a fixed $m(\tilde{t}_1)-m(\tilde{\chi}^0_1) = 180$ GeV and assuming a $\text{BR}(\tilde{t}_2 \to Z\tilde{t}_1) = 1$.

Expected exclusion limits at 95% CL from the analysis of $36.1 \; \text{fb}^{-1}$ of 13 TeV $pp$ collision data as a function of the masses of the $\tilde{t}_2$ and $\tilde{\chi}^0_1$, for a fixed $m(\tilde{t}_1)-m(\tilde{\chi}^0_1) = 180$ GeV and assuming a $\text{BR}(\tilde{t}_2 \to h\tilde{t}_1) = 1$.

Observed exclusion limits at 95% CL from the analysis of $36.1 \; \text{fb}^{-1}$ of 13 TeV $pp$ collision data as a function of the masses of the $\tilde{t}_2$ and $\tilde{\chi}^0_1$, for a fixed $m(\tilde{t}_1)-m(\tilde{\chi}^0_1) = 180$ GeV and assuming a $\text{BR}(\tilde{t}_2 \to h\tilde{t}_1) = 1$.

This paper presents a study of the production of $WW$ or $WZ$ boson pairs, with one $W$ boson decaying to $e\nu$ or $\mu\nu$ and one $W$ or $Z$ boson decaying hadronically. The analysis uses 20.2 fb$^{-1}$ of $\sqrt{s}=8$ TeV $pp$ collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for $WW/WZ$ production are measured in high-$p_{T}$ fiducial regions defined close to the experimental event selection. The cross-section is measured for the case where the hadronically decaying boson is reconstructed as two resolved jets, and the case where it is reconstructed as a single jet. The transverse momentum distribution of the hadronically decaying boson is used to search for new physics. Observations are consistent with the Standard Model predictions, and $95\%$ confidence intervals are calculated for parameters describing anomalous triple gauge-boson couplings.